package me.seu.demo.service.emqx;

import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttTopic;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;

/**
 * 订阅客户端
 *
 * @author liangfeihu
 * @number 53669
 * @since 2021/4/28 下午5:11
 */
public class SubscribeClientTwo {
    public static final String HOST = "tcp://127.0.0.1:1883";
    public static final String TOPIC = "device_config2";
    private static final String clientId = "emqx_test_java_three";

    private MqttClient client;
    private MqttConnectOptions options;
    private String userName = "emqx_test";
    private String passWord = "emqx_test_pwd";

    private void start() {
        try {
            // host为主机名，test为clientid即连接MQTT的客户端ID，一般以客户端唯一标识符表示，
            // MemoryPersistence设置clientid的保存形式，默认为以内存保存
            client = new MqttClient(HOST, clientId, new MemoryPersistence());
            // MQTT的连接设置
            options = new MqttConnectOptions();
            // 设置是否清空session,这里如果设置为false表示服务器会保留客户端的连接记录，
            // 这里设置为true表示每次连接到服务器都以新的身份连接
            options.setCleanSession(true);
            // 设置连接的用户名
            options.setUserName(userName);
            // 设置连接的密码
            options.setPassword(passWord.toCharArray());
            // 设置超时时间 单位为秒
            options.setConnectionTimeout(10);
            // 设置会话心跳时间 单位为秒
            // 服务器会每隔1.5*20秒的时间向客户端发送个消息判断客户端是否在线，但这个方法并没有重连的机制
            options.setKeepAliveInterval(20);
            // 设置回调
            client.setCallback(new OnMessageCallback2());

            MqttTopic topic = client.getTopic(TOPIC);
            // setWill方法，如果项目中需要知道客户端是否掉线可以调用该方法。
            // 设置最终端口的通知消息
            options.setWill(topic, "close".getBytes(), 0, true);

            client.connect(options);
            // 订阅消息
            int[] Qos = {1};
            String[] topics = {TOPIC};
            client.subscribe(topics, Qos);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void disconnect() {
        try {
            client.disconnect();
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }


    public static void main(String[] args) throws MqttException {
        SubscribeClientTwo client = new SubscribeClientTwo();
        client.start();
    }

}
